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# SC.6.P.13.3

Investigate and describe that an unbalanced force acting on an object changes its speed, or direction of motion, or both.
Subject Area: Science
Body of Knowledge: Physical Science
Idea: Level 2: Basic Application of Skills & Concepts
Big Idea: Forces and Changes in Motion - A. It takes energy to change the motion of objects.

B. Energy change is understood in terms of forces--pushes or pulls.

C. Some forces act through physical contact, while others act at a distance.

Clarification for grades K-5: The target understanding for students in the elementary grades should focus on Big Ideas A, B, and C.

Clarification for grades 6-8: The target understanding for students in grades 6-8 should begin to transition the focus to a more specific definition of forces and changes in motion. Net forces create a change in motion. A change in momentum occurs when a net force is applied to an object over a time interval.

Grades 9-12, Standard 12: Motion - A. Motion can be measured and described qualitatively and quantitatively. Net forces create a change in motion. B. Momentum is conserved under well-defined conditions. A change in momentum occurs when a net force is applied to an object over a time interval.

Date of Last Rating: 05/08
Status: State Board Approved
Assessed: Yes

### TEST ITEM SPECIFICATIONS

• Item Type(s): This benchmark will be assessed using: MC item(s)
• Also Assesses
SC.6.P.12.1 Measure and graph distance versus time for an object moving at a constant speed. Interpret this relationship.

• Clarification :
Students will describe and/or explain that an unbalanced force acting on an object changes its speed and/or direction.

Students will interpret and/or analyze graphs of distance and time for an object moving at a constant speed.
• Content Limits :
Items requiring the interpretation and/or analysis of a graph may assess the relative speed of an object at various points or sections of the graph and the direction of motion.

Items will not require a comparison of the speeds of more than five different objects.

Items will not assess the addition of nonparallel vectors.

Items will not require the calculation of acceleration.

Items may require the calculation of net force.

Items may assess the direction of net force.

Items addressing force and motion are limited to conceptual understanding.

Items will not require the use of the formula F=ma.

Items addressing changes in speed should use the terms positive acceleration and negative acceleration.

Items may assess understanding of friction as a force in both sliding and stationary situations. Items will not require knowledge of coefficient of friction.

Items will not imply that a calculation is required in scenarios assessing understanding of no acceleration or no net force.
• Stimulus Attributes :
Force diagrams may have a maximum of two sets of parallel forces acting on an object.

Scenarios addressing the calculation of average speed will not require the calculation of speed using data from a graph.

Graphs of distance and time may include no more than five constant speeds.
• Response Attributes :
Responses will not require the creation of graphs.
• Prior Knowledge :
Items may require the student to apply science knowledge described in the NGSSS from lower grades. This benchmark requires prerequisite knowledge from SC.3.P.10.2, SC.4.P.10.2, SC.4.P.10.4, SC.4.P.12.1, SC.4.P.12.2, SC.5.P.10.2, SC.5.P.13.2, SC.5.P.13.3, and SC.5.P.13.4.

### SAMPLE TEST ITEMS (1)

• Test Item #: Sample Item 1
• Question: The diagram below shows forces acting on a model airplane. Both its speed and height above the ground are constant.

Which of the following conditions would cause the model airplane to descend toward the ground?
• Difficulty: N/A
• Type: MC: Multiple Choice